code: def test_dataloaders():
      train_input = DatasetInput(RunningStage.TRAINING, DummyDataset())
      val_input = DatasetInput(RunningStage.VALIDATING, DummyDataset())
      test_input = DatasetInput(RunningStage.TESTING, DummyDataset())
      dm = DataModule(
          train_input,
          val_input,
          test_input,
          num_workers=0,
          batch_size=1,
      )
      for dl in [
          dm.train_dataloader(),
          dm.val_dataloader(),
          dm.test_dataloader(),
      ]:
          x = next(iter(dl))[DataKeys.INPUT]
          assert x.shape == (1, 1, 28, 28)
  
file_path: lightning-flash/tests/core/test_data.py
imports: import pytest
  import torch
  from flash import DataKeys, DataModule, RunningStage
  from flash.core.data.data_module import DatasetInput
  from flash.core.utilities.imports import _TOPIC_CORE_AVAILABLE
label_desc: Use image node_id 2 for calling a global function with example usage: test_dataloaders() without return types